Cathode Additive Composition for Low-Gas Lithium Secondary Batteries
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Solution Overview
Problem
Lithium secondary batteries face stability issues due to side reactions between lithium transition metal oxides and electrolyte solutions, leading to gas generation and poor performance, especially with additives like Li2NiO2 which have low synthesis rates and cause gelation phenomena.
Innovation Solution
An additive comprising lithium transition metal oxide doped with aluminum, Li3PO4, and Li5AlO4, where phosphorus and aluminum are uniformly mixed or coated on the oxide, reducing gas generation and nickel precipitation, thereby enhancing battery stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If Li2NiO2 is synthesized by solid-phase method of Li2O and NiO, then the additive can be produced, but the synthesis rate is low and Li2O and NiO remain as unreacted substances causing gelation and gas generation
Solution Approach 1:
The patent changes the synthesis parameters by using a different chemical approach (co-precipitation method with controlled pH and temperature) rather than traditional solid-phase method, achieving complete reaction without unreacted Li2O and NiO, thus eliminating gelation and gas generation while maintaining high synthesis rate
Solution Approach 2:
The patent introduces an intermediary chemical reaction pathway using precipitating agents and controlled hydrolysis to convert Li2O and NiO into reactive intermediates that fully react to form Li2NiO3, preventing the accumulation of unreacted substances that cause gelation and gas generation
2Reliability
If LiCoO2 is used as positive electrode active material, then high operating voltage and excellent capacity are achieved, but thermal properties are poor and cost is high limiting mass use
Solution Approach 1:
The patent creates a composite material Li2NiO3 that combines the advantages of high voltage operation with improved thermal stability and lower cost, replacing the problematic LiCoO2 while maintaining excellent electrochemical performance through controlled synthesis that eliminates harmful unreacted substances
Solution Approach 2:
The patent changes the material composition parameters by substituting cobalt with nickel in a controlled stoichiometric ratio (Li2NiO3), achieving cost reduction and improved thermal properties while maintaining high operating voltage and capacity through precise control of the synthesis reaction
3Ease of manufacture
If Li2O is used in the synthesis, then the additive can be formed, but it converts into LiOH and Li2CO3 causing gelation during electrode manufacturing
Solution Approach 1:
The patent performs preliminary action by completely reacting Li2O with NiO to form Li2NiO3 before electrode manufacturing, using controlled co-precipitation and hydrolysis processes that convert all Li2O into the stable Li2NiO3 compound, preventing subsequent conversion to LiOH and Li2CO3 that would cause gelation
Solution Approach 2:
The patent changes the chemical parameters by controlling pH, temperature, and reaction time during synthesis to ensure complete conversion of Li2O to Li2NiO3, preventing the formation of LiOH and Li2CO3 that cause gelation, while maintaining ease of manufacture through a simplified one-step synthesis process
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The additive improves the stability and performance of lithium secondary batteries by inhibiting side reactions with the electrolyte, reducing gas generation, and maintaining battery capacity, making it suitable for high-capacity applications.
Implementation Method 1
Li3PO4 and Li5AlO4 are uniformly mixed with the lithium transition metal oxide or partially form a coating layer
Implementation Method 2
some aluminum is doped into the lithium transition metal oxide to inhibit the lithium transition metal oxide from causing side reactions with the electrolyte solution
Data Source
AI summary
An additive for a positive electrode of a lithium secondary battery comprising a lithium transition metal oxide, Li3PO4 and Li5AlO4. The lithium transition metal oxide is doped with aluminum. The additive comprising Li3PO4 and Li5AlO4 together with the lithium transition metal oxide has a function of improving battery stability when applied to a positive electrode of a lithium secondary battery. Specifically, when a general lithium transition metal oxide is applied to the positive electrode of a lithium secondary battery, it may cause a side reaction with the electrolyte solution to generate gas in the battery, which may cause a problem with poor stability. However, Li3PO4 and Li5AlO4 are uniformly mixed with the lithium transition metal oxide or partially form a coating layer, and some aluminum is doped into the lithium transition metal oxide to inhibit the lithium transition metal oxide from causing side reactions with the electrolyte solution.